1. Field
The present invention relates to a peer mobile router authentication method, a multiple peer care-of addresses registration method using the same, a mobile router failover method for multi-homed mobile networks, and a computer readable recording medium storing a program for executing the methods.
2. Related Technology
Many scientist and companies expects that the next generation network will be evolved to have an A11-IP structure. Recently, a Wireless Broadband (WiBro) has intermediate characteristics of the wireless LAN and the third generation mobile communication network, and the related services thereof have been provided.
The WiBro aims for providing End-to-End IP communication services in Ubiquitous network environment.
In order to provide seamless wireless Internet access to users under the Ubiquitous network environment, it must support the mobility in the IP layer. As a standard for supporting the mobility, Internet Engineering Task Force (IETF) introduced a mobile IP scheme that supports the mobility in the IP layer. Also, a mobile IPv6 was standardized as Request for Comment (RFC) by applying the mobile IP scheme to IP version 6 (IPv6).
The mobile IPv6 allows a user to communicate with other users while the other users are traveling by assigning a Home Agent (HA), forcing a user to register to the assigned HA, and establishing a communication link between the users through the HA.
Generally, a user wants to access the wireless Internet using a portable terminal while traveling using vehicles such as a bus, a subway or an automobile. If each of users communicates each others using a mobile IP while traveling with vehicles such as a subway, all users must update the location information of own HA. Therefore, large load is generated by updating the location information of HA.
In order to overcome the shortcoming, the IETF formed a NEMO working group for supporting the network mobility and has been standardizing related specifications. The IETF introduced NEMO Basic support scheme. The NEMO Basic support scheme introduces a mobile router (MR) which is a router capable of traveling. In the NEMO Basic support scheme, only mobile router (MR) updates the location information of a Home Agent (HA) when the entire network moves. For example, the MR is installed at a vehicle. When the vehicle is moving, it treats as the entire network is moving, and the only MR updates the location information of the HA.
Multi-homing scheme is generally applied to a host or a network. The multi-homing scheme provides various advantages to a user or a service provider, such as failover, load distribution, and policy routing. The NEMO working group defines not to teach the multi-homing scheme in the NEMO Basic Support scheme but to teach the multi-homing scheme in NEMO Extended Support scheme later. Recently, various analyses have been in progress to apply the multi-homing scheme in the mobile network before introducing the multi-homing scheme.
Hereinafter, a method of registering multiple Care-of Addresses (CoA) will be described at first. Then, a method for authenticating and registering a neighbor mobile router will be described.
According to the mobile IPv6, a mobile node (MN) is allowed to register only one primary Care-of Address (CoA) to a home agent (HA) although a mobile node (MN) is allowed to receive multiple CoAs.
However, in order to supporting seamless mobility, a mobile node (MN) should have more than one network interfaces to access the Internet for failover and network load distribution.
Therefore, a method for registering multiple CoAs was introduced to allow a MN to register more than one CoAs to a HA through expanding the mobile IPv6. When the MN registers a CoA to a HA, a conventional mobile IPv6 adds a home address and a CoA entry to a binding cache if the home address of the MN is not in the binding cache. If the home address of the MN is in the binding cache, a corresponding CoA is updated. That is, the convention binding update (BU) does not allow a MN to use multiple CoAs because a corresponding entry is updated when new BU is performed for the home address of a MN that already register a CoA.
In order to allow the MN to use multiple CoAs, the method of registering multiple CoAs defines a flag M denoting multiple CoAs in a binding update packet. If the M flag is setup, it means that multiple CoAs are used for a home address. Additionally, a binding update mobility option field includes a binding unique identifier sub-option. Through the binding unique identifier sub-option, a binding unique identifier number (BID) is transferred, and the MN can identify each of network interfaces used by each of the CoAs through the BID. Meanwhile, if the M flag is not setup, the MN performs related operations identically to the conventional BU and does not register multiple CoAs.
As described above, the method for registering multiple CoAs allows the MN to register multiple CoAs for one home address to the own HA so as to provide seamless connection and superior service quality (QoS) although the load is distributed according to a pre-give policy or communication difficulty is arisen.
Hereinafter, a method for authenticating and registering a neighbor mobile router (MR) will be described.
In order to perform a failover or distribute loads in a mobile network, various multi-homing schemes allowing one or more routers to provide services were introduced.
When multiple mobile routers are present and one of the mobile routers is malfunctioned, other mobile routers perform the role of the malfunctioned mobile router and help other mobile router having large load.
In order to help other routers to recover or to distribute the large load, it requires that a peering relation between mobile routers is defined through authentication. That is, a MR detects the present of neighbor mobile routers and defines neighbor mobile routers to provide predetermined services instead of the malfunctioned MR or to distribute large load when the MR becomes malfunctioned or has the large load. The reason of authentication is to determine whether neighbor mobile routers have a capability to provide the predetermined service instead of the malfunctioned MR or to confirm whether adjacent mobile routers are corresponding neighbor routers. That is, the authentication checks the capability of adjacent mobile routers to provide the predetermined service instead of the malfunctioned MR or confirms whether adjacent mobile routers are corresponding neighbor routers. After successful authentication, the MR defines the authenticated mobile routers as the neighbor mobile routers.
Such a conventional method of authenticating and registering the neighbor mobile routers was not newly introduced. Return Routability (RR) scheme provided from a conventional mobile IPv6 is used for the authentication between mobile routers. For example, a first mobile router MR1 authenticates a second mobile router MR2 as a neighbor mobile router through a method shown in FIG. 1.
Referring to FIG. 1, the second mobile router MR1 may transmit a router solicitation (RS) message to the first mobile router MR1 to receive a router advertisement (RA) message from the first mobile router MR1.
Afterward, the second mobile router MR2 receives the RA message from the first mobile router MR1 and detects the home address and the CoA of the first mobile router MR1 from the received RA message. Then, the second mobile router MR2 performs the Return Routability (RR) such as RR initialization (HoTI (Home Test Init), CoTI (Care of Test Inti)) and RR response (CoT (Care of Test), HoT (Home Test)) using the home address and the CoA of the first mobile router MR1.
After successful authentication, the first mobile router MR1 registers the second mobile router MR2 to a first home agent HA1 of the first mobile router MR1 as a neighbor mobile router MR. Herein, the first mobile router MR1 transfers the home address, the CoA and the prefix information of the neighbor mobile router, that is, the second mobile router MR2, to the first home agent HA1. Accordingly, the first home agent HA1 has the information about the second mobile router MR2, and the first home agent HA1 uses the second mobile router MR2 when the first mobile router MR1 is malfunctioned.
As one of the multi-homing scenarios, the present invention relates to a method forcing a neighbor mobile router to provide the services of a malfunctioned mobile router in order to provide seamless service when one of mobile routers becomes malfunctioned in the NEMO network formed of multiple mobile routers. In the present invention, the conventional method for registering multiple CoAs, which was introduced for a conventional mobile IPv6 between authenticated mobile routers MR, is expanded to apply the conventional method into the NEMO network.
The foregoing discussion is only to provide the background information, not an admission of prior art.